Question

Describe as completely as you can the complete feedback system for the control of Oogenesis. Include in your answer:

                        a.         cells and cell types involved in regulating factor/tropic hormone/hormone production and secretion

                        b.         feedback loop and sites of influence for all hormone types

                        c.         physical and chemical changes to the major reproductive structures and secondary sexual characteristics of the individual.

                        d.         The stages and events in cellular division

Answer 1

a) Tropic hormones are hormones that have other endocrine glands as their target- most tropic hormones are produced and secreted by the anterior pituitary. The hypothalamus secretes tropic hormones that targets the anterior pituitary and the thyroid gland secretes thyroxine which targets the hypothalamus and therefore can be considered a tropic hormone.

The four tropic hormones of the anterior pituitary gland are:

1)Follicle- stimulating Hormone ( FSH)

2) Luteinzing Hormone ( LH)

3) Adrenocorticotropic Hormone ( ACTH)

4) Thyroid stimulating Hormone ( TSH )

b) Most hormones are regulated by feedback mechanisms. A feedback mechanism is a loop in which a product feed back to control it's iwn production. Most hormone feed back mechanisms involve negative feedback loops. Negative feedback keeps the concentration of a hormone within a narrow range. Hormone production and release are primarily controlled by negative feed back. In negative feed back systems, a stimulus causes the release of a substance whose effects then inhibit further release. In this way the concentration of hormones in blood is maintained within a narrow range.

Hormones are chemical messengers secreted into blood or Extracellular fluid by one cell that affect the functioning of other cells. Most hormones circulate in blood, coming into contact with essentially all cells. Hormones are secreted from the gland of the endocrine system, they are specific target organ that each hormone causes a response in a specific target organ or group of cells, rather than on the body as a whole. Exocrine hormones are secreted via a duct into the blood and usually effect a distant organ or tissue .

c) Secondary sexual characteristics are features that appear puberty in humans, and at sexual maturity in other animals. In humans, visible secondary sex characteristics includes, pubic hair, enlarged breasts and widnened hips of females and facial hair and Adam's apples on males.

d) Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gametes cells. This process is required to produce egg and sperm cells for sexual reproduction. Meiosis begins with a parent cell that is diploid, meaning it has two copies of each chromosomes.